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INDEPENDENT AND CONTRASTING EFFECTS OF ELEVATED CO2 AND N-FERTILIZATION ROOT ARCHITECTURE
Tingey, D T., M G. Johnson, AND D L. Phillips. INDEPENDENT AND CONTRASTING EFFECTS OF ELEVATED CO2 AND N-FERTILIZATION ROOT ARCHITECTURE. TREES. Springer-Verlag, New York, NY, 19(1):43-50, (2005).
The effects of elevated CO2 and N fertilization on architecture of Pinus ponderosa fine roots and their associated mycorrhizal symbionts were measured over a 4-year period. The study was conducted in open-top field-exposure chambers located near Placerville, CA. A replicated (three replicates), 3 x 3 factorial experimental design with three CO2 concentrations ambient air [~354 mol mol-1], 525 mol mol-1, and 700 mol mol-1 and 3 rates of N fertilization (0, 100 and 200 kg ha-1 yr-1) was used. However, the 100 kg ha-1 yr-1 N treatment at 525 mol mol-1 CO2 was omitted from the experimental design. Elevated CO2 and N treatment had contrasting effects on the architecture of fine roots and their associated mycorrhizae. Elevated CO2 increased both fine root extensity (degree of soil exploration) and intensity (extent that roots use explored areas) but had no effect on mycorrhizae. In contrast, N fertilization had no effect on fine root extensity or intensity but increased mycorrhizal extensity and intensity. To better understand and model the responses of systems to increasing CO2 concentrations and N deposition/fertilization it is necessary to consider these differing root architectural responses.
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY
WESTERN ECOLOGY DIVISION